Their widely recognized standards, such as the IEEE C37 series and IEC 60255 series, provide guidelines for the development, testing, and certification of relay protection devices. Certification bodies typically follow established procedures when evaluating relay protection. IEC standards define the specifications, performance criteria, communication protocols, and testing methods for protection relays. These standards aim to ensure uniformity and compatibility across different manufacturers. Protective Relay Definition: A protective relay is an automatic device that senses abnormal conditions in electrical circuits and triggers actions to isolate faults. Since the basic function of a protection relay is to correctly function under abnormal.